Actionscript 3 - How to Check if an Array Position Already Exists - arrays

Question

Hello my question is as stated. I have a randomly generated dungeon with a player and random blocks. All the rooms in the dungeon are saved in the ROOMS 2D array which contains the data for the rooms. You have a current Row and current Col which is where the player is at. What i need to know is how to say IF there is no room above the current position then change the outside wall graphic to close the exits/doors where there is no room. I have this somewhat working but everyway i change it there is always one room which just will not work if i try to add the code. What i have now is abunch of if statements saying IF ROOMS[currentRow + 1][currentCol](< that would be equal to down) so if one row up exists then change the graphic by doing gotoAndStop. So how or which is the best way to determine if a position exists because with this, it will randomly comeback with errors like "term is undefined and has no properties." Also i have really dirty code, sorry im new, ill try to clean it up later but if any of you feel like it, i wont stop you haha!
Im grateful for any replies! Here is my room class
package {
import flash.display.MovieClip;
import flash.events.Event;
public class Room extends MovieClip{
var room1:Array = new Array();
var room2:Array = new Array();
var room3:Array = new Array();
var room4:Array = new Array();
var room5:Array = new Array();
var room6:Array = new Array();
var room7:Array = new Array();
var room8:Array = new Array();
var room9:Array = new Array();
var room10:Array = new Array();
var currentRow:int = 0;
var currentCol:int = 0;
var box:Box;
var boxes:Array;
var ROOMS:Array;
var onTop:Boolean;
var moved:Boolean;
private var player:Player;
private var walls:Walls;
private var blocker1:Blocker;
private var blocker2:Blocker;
private var blocker3:Blocker;
private var blocker4:Blocker;
private var arrowImage:ArrowSymbol;
public function Room(){
init();
createRooms();//add the walls + boxes of first room to the first array value // later make floors array that contains all the rooms and room array that contains all the boxes and enemies + events
stage.addChild(ROOMS[currentRow][currentCol]);
Constants.wallsRef = ROOMS[currentRow][currentCol];
addEventListener(Event.ENTER_FRAME, update);
stage.addChild(arrowCount);
stage.addChild(arrowImage);
}
function init(){
Constants.stageRef=stage;
player = new Player();
//add walls
walls = new Walls();
Constants.wallsRef=walls;
blocker1 = new Blocker();//BLOCKER WHEN PLAYER TOUCHES IT CHANGES ROOM
blocker1.x = 350;
blocker1.y = 1;
stage.addChild(blocker1);
blocker2 = new Blocker();
blocker2.x = 350;
blocker2.y = 619;
stage.addChild(blocker2);
blocker3 = new Blocker();
blocker3.x = -30;
blocker3.y = 300;
blocker3.rotation = 90;
stage.addChild(blocker3);
blocker4 = new Blocker();
blocker4.x = 700;
blocker4.y = 300;
blocker4.rotation = 90;
stage.addChild(blocker4);
Constants.blockerRef1 = blocker1;
Constants.blockerRef2 = blocker2;
Constants.blockerRef3 = blocker3;
Constants.blockerRef4 = blocker4;
//add player
player.x = 300;
player.y = 200;
stage.addChild(player);
arrowImage = new ArrowSymbol();
arrowImage.x = 630;
arrowImage.y = 30;
box = new Box();
boxes = new Array();
ROOMS = new Array([room2],
[room6, room1, room5], /// THIS IS THE MAP OF THE FLOOR /// GOING UP ON THE GAME IS GOING DOWN ON IT
[room7, room8],
[room3, room9],
[room4]);//THIS WILL EVENTUALLY BE COMPLETELY RANDOMIZED//
onTop = false;
moved = false;
}
function update(e:Event){
arrowCount.text = " " + Constants.arrowNumRef;//arrow amount left
closeUnnecessaryExits();
//UP
if(Constants.blockerRef1.hitTestPoint(player.x,player.y) && moved != true){
stage.removeChild(ROOMS[currentRow][currentCol]);//remove the room you are in so the new room doesnt overlap
currentRow++;//change where the player is in
stage.addChild(ROOMS[currentRow][currentCol]);//add new room
Constants.wallsRef = ROOMS[currentRow][currentCol];//add colision
player.y = 600;
stage.addChild(arrowCount);
stage.addChild(arrowImage);
trace();
moved = true;
}else if(Constants.playerRef.hitTestObject(Constants.blockerRef1) == false && moved == true){
moved = false;
}
//DOWN
if(Constants.blockerRef2.hitTestPoint(player.x,player.y) && moved != true){
//this will be where i want to change rooms
stage.removeChild(ROOMS[currentRow][currentCol]);
currentRow--;
Constants.wallsRef = ROOMS[currentRow][currentCol];
stage.addChild(ROOMS[currentRow][currentCol]);
player.y = 10;//change to 600
moved = true;
trace("changed rooms");
stage.addChild(arrowCount);
stage.addChild(arrowImage);
}else if(Constants.playerRef.hitTestObject(Constants.blockerRef1) == false && moved == true){
moved = false;
}
//LEFT
if(Constants.blockerRef3.hitTestPoint(player.x,player.y) && moved != true){
stage.removeChild(ROOMS[currentRow][currentCol]);//remove the room you are in so the new room doesnt overlap
currentCol--;//change where the player is in
stage.addChild(ROOMS[currentRow][currentCol]);//add new room
Constants.wallsRef = ROOMS[currentRow][currentCol];//add colision
player.x = 600;
stage.addChild(arrowCount);
stage.addChild(arrowImage);
moved = true;
}else if(Constants.playerRef.hitTestObject(Constants.blockerRef1) == false && moved == true){
moved = false;
}
//RIGHT
if(Constants.blockerRef4.hitTestPoint(player.x,player.y) && moved != true){
//this will be where i want to change rooms
stage.removeChild(ROOMS[currentRow][currentCol]);
currentCol++;
Constants.wallsRef = ROOMS[currentRow][currentCol];
stage.addChild(ROOMS[currentRow][currentCol]);
player.x = 10;//change to 600
moved = true;
trace("changed rooms");
stage.addChild(arrowCount);
stage.addChild(arrowImage);
}else if(Constants.playerRef.hitTestObject(Constants.blockerRef1) == false && moved == true){
moved = false;
}
}
function createRooms(){
for(var r = 0; r <ROOMS.length; r++){
walls = new Walls();
addRandomBlocks();
for(var c = 0; c < ROOMS[r].length; c++){
walls = new Walls();
addRandomBlocks();
ROOMS[r][c] = walls;
}
trace(ROOMS[r][c]);
}
}
// [room2, NaN],
// [room6, room1, room5], /// THIS IS THE MAP OF THE FLOOR /// GOING UP ON THE GAME IS GOING DOWN ON IT
// [room7, room8],
// [room3, room9],
// [room4]);
function closeUnnecessaryExits(){
trace("ROW: " + currentRow + " COL: " + currentCol);
var up = ROOMS[currentRow + 1];
var down = ROOMS[currentRow - 1];
var right = ROOMS[currentRow][currentCol + 1];
var left = ROOMS[currentRow][currentCol - 1];
//check to see which outside wasall to use
if(ROOMS[currentRow + 1] == null && up && right && left){
ROOMS[currentRow][currentCol].gotoAndStop(2);
}else if(down == null && left == null && right && up){
ROOMS[currentRow][currentCol].gotoAndStop(3);
}else if(down == null && left == null && up == null && right){
ROOMS[currentRow][currentCol].gotoAndStop(4);
}else if(left == null && down && right && up){// IF HAVING PROBLEMS THEN MAKE THIS MAKE SURE ALL OTHER SIDES ARE TRUE
ROOMS[currentRow][currentCol].gotoAndStop(5);
}else if(down == null && left == null && right == null && up){
ROOMS[currentRow][currentCol].gotoAndStop(6);
}else if(down && up == null && right == null && left == null){
ROOMS[currentRow][currentCol].gotoAndStop(7);
}else if(ROOMS[currentRow + 1][currentCol] == null && ROOMS[currentRow - 1][currentCol] && left && right){
ROOMS[currentRow][currentCol].gotoAndStop(8);
trace("works 1");
}else if(left && right && ROOMS[currentRow - 1][currentCol] == null && ROOMS[currentRow + 1][currentCol] == null){
ROOMS[currentRow][currentCol].gotoAndStop(9);
trace("works 2");
}else if(left && ROOMS[currentRow - 1][currentCol] && right == null && ROOMS[currentRow + 1][currentCol] == null){
ROOMS[currentRow][currentCol].gotoAndStop(10);// LEFT DOWN
trace("works 3");
}else if(left && ROOMS[currentRow + 1][currentCol] && ROOMS[currentRow - 1][currentCol] == null && right == null){
ROOMS[currentRow][currentCol].gotoAndStop(11);//BROKEN left up
trace("working 4");
}else if(left && ROOMS[currentRow + 1][currentCol] == null && ROOMS[currentRow - 1][currentCol] == null && right == null){
ROOMS[currentRow][currentCol].gotoAndStop(12);
trace("works 5");
}else if(right == null && left && up && down){
ROOMS[currentRow][currentCol].gotoAndStop(13);
trace("works 6");
}
}
function addRandomBlocks(){
for(var e=0; e <Math.random() * 10; e++){
//trace("started block");
box = new Box();
box.x = Math.random() * (615 - 100) + 100;
box.y = Math.random() * (500 - 120) + 120;
//colision for block to block
for(var col = 0; col < boxes.length; col++){
if(box.hitTestObject(boxes[col])){
onTop = false;/// THIS NEEDS TO BE TRUE FOR THE DETECTION TO WORK
//trace("THIS BOX IS ON TOP OF ANOTHER");
}
}
if(onTop == false){
boxes.push(box);
walls.addChild(box);
trace("BOX CREATED " + onTop);
//trace(boxes);
}
}
}
}
}

Answer 1

You could streamline your code by creating some simple functions that deal with assigning and accessing values in your 2D array. One that checks if an element within a 2D array exists might look like:
function cellExists(array:Array, x:int, y:int):Boolean {
return array[y] !== undefined && array[y][x] !== undefined;
}
Used like, in your example:
if (cellExists(ROOMS, currentCol, currentRow)) {
//
}
Although with this type of task you would benefit greatly from implementing a class that handles grid + cell data, something along the lines of this to get you started:
public class Grid {
private var _content:Vector.<Vector.<Cell>>;
public function Grid(columns:int, rows:int) {
// Fill _content with empty slots based on columns, rows.
}
public function getCell(x:int, y:int):Cell {}
public function cellExists(x:int, y:int):Boolean {}
}